The present invention relates to conveyor belts that are used to carry objects or articles from one location to another.
Plastic conveyor belts are well known in the art. For example, Palmaer, U.S. Pat. No. 4,742,907 described a plastic conveyor belt.
Designing a conveyor belt to go straight is difficult. Designing a conveyor belt to turn or go up and down an incline is even more difficult.
The conveyor belt of the ""907 patent is able to traverse curves. The individual belt links can move closer to or away from adjacent links. This property is useful for traversing curves, wherein at the inside of the curve, the belt links are close together, and at the outside of the curve, the belt links are spread apart. The belt has gaps between the links for traversing curves. The gaps also allow air to circulate through the belt, an advantage when the belt conveys foods.
Adapting the belt to other applications presents some problems. In the package handling and baggage industries, the objects being conveyed are subject to being caught in the gaps between the links. For example, baggage has straps, hooks, wheels, handles, etc. which can become easily captured between two links. Packages may be flimsy envelopes, which can also become caught. A bag or package that becomes caught by the conveyor belt risks damage to itself and to the conveyor belt.
Another problem is speed. Packages and baggage are most desirably conveyed at high speeds, such as 300 feet per minute. This is in contrast with the much lower speed of the food handling industry (for example, 50 feet per minute). Higher speeds produce greater forces exerted on the belt. In addition, the links produce a loud and undesirable chatter at high speeds.
The loading on conveyor belts used in the package industry is much greater than those encountered in the food industry. The loading in the food handling industry is 10-13 pounds per linear foot, while it is 50 pounds per linear foot in the package industry (for a 36xe2x80x3 wide belt).
It is an object of the present invention to provide a conveyor belt that can be used in the baggage or package industry without the problems discussed above.
The present invention provides a link for a plastic conveyor belt. The belt is constructed of links interconnected by pivot rods in a sequence of hinged links for conveying articles along a path, which path may include a curved portion. The link includes a rib, a first set of projections and a second set of projections. The first set of projections extends from the rib in a first direction. The individual projections of the first set are separated from each other by respective first gaps. The projections of the first set each have an opening therethrough. The openings in the first set of projections are aligned so as to receive a first pintle. The second set of projections extends from the rib in a direction that is opposite of the first direction. The individual projections of the second set are separated from each other by respective second gaps. The projections of the second set are staggered with respect to the projections of the first set. The projections of the second set each having a slotted opening therethrough. Each of the slotted openings extend for a portion of the length of the respective projection of the second set. The openings in the second set of projections are aligned so as to receive a second pintle. The rib, the first set of projections and the second set of projections collectively have a first side and a second side. The projections of the first and second sets each have a length. A cover member is located on the first side. The cover member overlies a portion of the lengths of the projections of the first and seconds sets so as partially cover the first and second gaps.
In accordance with one aspect of the present invention, the rib has ends, with the first set of projections having first endmost projections located at the ends of the rib and the second set of projections having second endmost projections located at the ends of the rib. The cover members couple to the first and second endmost projections.
In accordance with another aspect of the present invention, the cover member extends from the rib along the lengths of the projections of the first and second sets a distance that is:
distancexe2x89xa7length of the projections of respective setxe2x88x92(A+B+C)
where A=the distance between the end of a projection in the first set and the opening in the projection
B=the distance between the end of a projection in the second set and the opening in the projection
C=the diameter of the pivot rod.
In accordance with still another aspect of the present invention, the link has a stepped first side, with a step being formed between the first set of projections and the cover member and another step being formed between the second set of projections and the cover member.
In accordance with still another aspect of the present invention, the cover member has a carrying surface facing away from the rib. The carrying surface has a groove therein.
In accordance with still another aspect of the present invention, the link has two ends with the cover member extending between the ends. The cover member has beveled portions at each of the ends to accommodate the curved path.
In accordance with another aspect of the present invention, the link has two ends, with each end having a slot therein. The slot is parallel to the first and second sets of projections. The slot being structured and arranged to receive a guide rail.
In accordance with still another aspect of the invention, the slot has an inside surface that is structured and arranged to contact the guide rail. The inside surface is arcuate so as to be convex.
In still another aspect of the present invention, each of the link ends has outside end surfaces with the slot in each end being between the outside end surfaces. The outside end surfaces are each arcuate so as to be convex.
The present invention also provides a link for a plastic conveyor belt, the belt being constructed of links interconnected by pivot rods into a sequence of hinged links for conveying articles along a path which path may include a curved path. The link includes a rib, a first set of projections and a second set of projections. The first set of projections extends from the rib in a first direction. The individual projections of the first set are separated from each other by respective first gaps. The projections of the first set each having an opening therethrough. The openings in the first set of projections being aligned so as to receive a first pivot rod. The second set of projections extends from the rib in a direction that is opposite of the first direction. The individual projections of the second set are separated from each other by respective second gaps. The projections of the second set are staggered with respect to the projections of the first set. The projections of the second set each have a slotted opening therethrough. Each of the slotted openings extends for a portion of the length of the respective projection of the second set. The openings in the second set of projections being aligned so as to receive a second pivot rod. The link has two ends, with the rib extending between the ends. A slot is formed in each end of the link. Each slot is formed by a pair of walls extending from an endmost projection in either the first or second sets of projections. The endmost projections are at respective ends of the rib.
In accordance with another aspect of the invention, each of the slots has an inside surface that is structured and arranged to contact a guide rail. The inside surface is arcuate so as to be convex.
In accordance with still another aspect of the present invention, each of the walls that extend from the endmost projection to form the slot has an outside end surface. The outside end surfaces are arcuate so as to be convex.
The present invention also provides a conveyor belt system for carrying articles along a path which path may include a curved path. First and second conveyor belts are located side by side adjacent to each other. The first and second conveyor belts are guided along respective paths by tracks. Each of the first and second conveyor belts includes a plurality of links, with each of the links comprising a rib, a first set of projections and a second set of projections. The first set of projections extends from the rib in a first direction. The individual projections of the first set being separated from each other by respective first gaps. The projections of the first set each having an opening therethrough. The openings of the first set of projections are aligned so as to receive a first pivot rod. The second set of projections extends from the rib in a direction that is opposite of the first direction. The individual projections of the second set are separated from each other by respective second gaps. The projections of the second set are staggered with respect to the projections of the first set. The projections of the second set each having a slotted opening therethrough. Each of the slotted openings extends for a portion of the link of the respective projection of the second set. The openings of the second set of projections being aligned so as to receive a second pivot rod. The link has two ends with the rib extending between the ends. A slot is formed in each of the link. Each slot is formed by a pair of walls extending from an endmost projection in either the first or second sets of projections. The endmost projections being at the respective ends of the rib. The end slots receive the tracks, there being a center guide serving as a center track between the first and second conveyor belts. The center guide has first and second lips extending in opposite directions from each other. The first and second lips are coupled to mounting structure by a web. The first and second lips are received in end slots of the links in the first and second conveyor belts.
In accordance with another aspect of the present invention, the first and second lips comprise metal with plastic being interposed between the first and second lips on the conveyor belt links.
The present invention also provides a conveyor belt system for carrying articles along a path. There is a plurality of plastic links, with each link having a rib, a first set of projections and a second set of projections. The first set of projections extends from the rib in a first direction. The individual projections of the first set being separated from each other by respective first gaps. The projections of the first set each having an opening therethrough. The openings of the first set of projections are aligned so as to receive a first pivot rod. The second set of projections extends from the rib in a direction that is opposite of the first direction. The individual projections of the second set are separated from each other by respective second gaps. The projections of the second set are staggered with respect to the projections of the first set. The projections of the second set each having a slotted opening therethrough. The slotted opening extends for a portion of the length of the projection of the second set. The openings of the second set of projections being aligned so as to receive a second pivot rod. The links being coupled together with the pivot rods such that the first set of projections are received by the second gaps and the second set of projections are received by the first gaps. Each of the links having two ends with each of the ends having a slot therein. The slot is parallel to the first and second sets of projections. There are two side frames that are spaced apart from each other. Each side frame has first and second lips. The first and second lips extend in an inside direction and are separated from each other by one or more cross members that couple the side frames together. The conveyor belt has an upper portion and a lower portion, with the slots of the belt links in the upper portion of the conveyor belt receiving the first lips and the slots of the belt links in the lower portion of the conveyor belt receiving the second lips.
The side frames and cross members form a self-contained support assembly for the conveyor belt.
In accordance with another aspect of the present invention, the side frames have outside surfaces which outside surfaces engage vertical supports.